U.S. patent application number 14/914873 was filed with the patent office on 2016-07-21 for compounder-injection-molding unit.
This patent application is currently assigned to HP PELZER HOLDING GMBH. The applicant listed for this patent is HP PELZER HOLDING GMBH. Invention is credited to Thomas BUCKI, Joerg GERIGK, Thomas KARCZ, Norbert NICOLAI, Tariq OWEIMREEN, Volkmar SCHULZE.
Application Number | 20160207241 14/914873 |
Document ID | / |
Family ID | 51541058 |
Filed Date | 2016-07-21 |
United States Patent
Application |
20160207241 |
Kind Code |
A1 |
GERIGK; Joerg ; et
al. |
July 21, 2016 |
COMPOUNDER-INJECTION-MOLDING UNIT
Abstract
The invention concerns a compounder-injection-molding unit,
wherein a continuously operating compounder is coupled to a
discontinuously operating screw injection-molding machine.
Inventors: |
GERIGK; Joerg; (Dorsten,
DE) ; OWEIMREEN; Tariq; (Denver, CO) ;
SCHULZE; Volkmar; (Schierling, DE) ; KARCZ;
Thomas; (Dortmund, DE) ; BUCKI; Thomas;
(Dorsten, DE) ; NICOLAI; Norbert;
(Schermbeck-Gahlen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HP PELZER HOLDING GMBH |
Witten |
|
DE |
|
|
Assignee: |
HP PELZER HOLDING GMBH
Witten
DE
|
Family ID: |
51541058 |
Appl. No.: |
14/914873 |
Filed: |
September 5, 2014 |
PCT Filed: |
September 5, 2014 |
PCT NO: |
PCT/EP2014/068968 |
371 Date: |
February 26, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 2948/926 20190201;
B29C 2945/76408 20130101; B29C 45/77 20130101; B29C 45/47 20130101;
B29C 2945/76183 20130101; B29C 45/46 20130101; B29C 2045/466
20130101; B29C 2945/76107 20130101 |
International
Class: |
B29C 45/47 20060101
B29C045/47; B29C 45/77 20060101 B29C045/77 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 11, 2013 |
DE |
10 2013 218 193.0 |
Claims
1. A compounder-injection-molding unit comprising a compounder (1),
especially a twin-screw extruder, for producing a materially and
thermally homogeneous compound melt of at least one plastic
material and further additives; and a screw-type injection molding
machine (2) with a standard feed zone (6), characterized in that
the exit of the compounder (1) is directly connected with the
standard feed zone (6) of the screw-type injection molding machine
(2) through a connecting unit (8) without counter-pressure from the
screw-type injection molding machine (2), said injection molding
machine (2) has a feed space as a reservoir (10) for a compound
continuously produced by the compounder (1); a conveying screw (5)
positioned within the screw-type injection molding machine (2); and
said injection molding machine (2) has a sensor (7) for measuring
the filling level of the injection molding machine (2) and
controlling the operation of compounder (1).
2. The compounder-injection-molding unit according to claim 1,
characterized in that the screw (5) communicates with the
connecting unit (8) via the standard feed zone (6) which is
designed in such a way that the compound present in the reservoir
(10) is always metered completely into the subsequent injection
molding cycle/metering cycle of the injection molding machine
(2).
3. The compounder-injection-molding unit according to claim 1,
characterized in that the connecting unit (8) has a valve (9) for
discharging inhomogeneous compound during the start-up and of any
compound that is not needed.
4. The compounder-injection-molding unit according to claim 1,
characterized in that the connecting unit (8) is positioned along
the cylinder of the screw-type injection molding machine (2) in the
zone of the first third of the screw (5) in the conveying direction
from the standard feed zone (6).
5. The compounder-injection-molding unit according to claim 1
characterized in that a filling level sensor (7) is provided in the
standard feed zone (6) of the screw-type injection molding machine
(2).
6. The compounder-injection-molding unit according to claim 1,
characterized in that the channel volume of the screw (5) is
adapted to the metering volume.
7. The compounder-injection-molding unit according to claim 1,
characterized in that the compound is directly conveyed into the
standard feed zone (6) of the screw-type injection molding machine
(2), and the controlling is effected through a filling level sensor
(7).
Description
FIELD OF THE INVENTION
[0001] The invention relates to a compounder-injection-molding unit
in which a continuously working compounder is coupled with a
discontinuously working screw-type injection molding machine.
BACKGROUND
[0002] Different designs of injection units coupled with a
compounding unit are known from the prior art. The compounder is
preferably a twin-screw extruder, which is co-rotating or
counter-rotating depending on the type of material. The injection
unit is preferably a piston-type injection molding machine.
Solutions in which the compounder works continuously and the
injection molding machine works discontinuously are applied in
practice. During the injection process, the injection molding
machine cannot take up material. The storage or processing of the
material then distinguishes the individual solutions.
[0003] A compounder-injection-molding unit in which 2 injection
molding machines are alternately supplied with the melt by a
continuously working twin-screw extruder is known from EP 1 144 174
B1.
[0004] The first in/first out is achieved here by a flow that
continuously goes in one direction.
[0005] Another solution is known from EP 1 306 187 B1. In this
solution, a material reservoir is provided between the injection
molding unit and the compounder. A stop valve towards the reservoir
prevents backflow during the injection process.
[0006] EP 1 333 968 B1 and U.S. Pat. No. 2,950,501 A describe a
solution in which a defined cleft between the piston and cylinder
serves for the continuous transport of the melt into the injection
space. A uniform filling is to be achieved through manifold
channels.
[0007] In EP 2 050 554 A1, a compound is conveyed into the
injection machine under counter-pressure with corresponding screw
geometries.
[0008] In U.S. Pat. No. 6,875,385 B2, a fibrous material is coated
with a melt under pressure.
[0009] Johannaber, F.; "Injection molding machines: a user's
guide", Carl Hanser publishers, Munich, Vienna, New York, 1994,
pages 242 and 243, relates to general prior art.
[0010] In WO 2009/147227 A1, in a similar solution, the material is
conveyed into the injection space through channels in the piston or
cylinder. The realization of the first in/first out principle is
said to be advantageous over the aforementioned solution.
[0011] In another embodiment, WO 01/78963 A1 describes an injection
unit for a piston-type injection molding machine with an extruder
as the plastification unit. The front end of the extruder is
connected with the injection space of the piston-type injection
unit through a melt line. The melt line has a stop valve. When the
stop valve is closed, the back-pressure length increases backwards
into the extruder.
SUMMARY OF THE INVENTION
[0012] It is the object of the present invention to provide a
compounder-injection-molding unit consisting of commercially
available components (plants) without substantial reconstruction in
which the continuously obtained homogeneous compound melt is
continuously stored in a discontinuously working screw-type
injection molding machine 2 during the injection molding process,
or buffered in such a way that the reservoir 10 is emptied
completely in the next injection molding cycle.
[0013] In the broadest sense the present invention concerns a
compounder-injection-molding unit comprising a compounder (1),
especially a twin-screw extruder, for producing a materially and
thermally homogeneous compound melt of at least one plastic
material and further additives; and a screw-type injection molding
machine
(2) with a standard feed zone (6), characterized in that the exit
of the compounder (1) is directly connected with the standard feed
zone (6) of the screw-type injection molding machine (2) through a
connecting unit (8) without counter-pressure from the screw-type
injection molding machine (2), said injection molding machine (2)
has a feed space as a reservoir (10) for a compound continuously
produced by the compounder (1); and a sensor (7) of compounder (1)
for measuring the filling level.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] The invention relates to a compounder-injection-molding unit
comprising a compounder 1, especially a twin-screw extruder 3, for
producing a homogeneous melt of at least one plastic material and
further additives, and a screw-type injection molding machine 2
connected with compounder 1.
[0015] The connection of the compounder 1 to the injection molding
machine 2 can be realized in different zones of the cylinder of the
injection molding machine 2. According to the invention, the
compounder 1 is connected with the injection molding machine 2 in
such a way that the zone of the injection molding screw 5 from the
material supply from the compounder 1 to the standard material
providing part 6 (standard hopper of the screw-type injection
molding machine 2) represents a reservoir 10 for the material
continuously produced by compounder 1.
[0016] In a first embodiment, the present invention relates to a
compounder-injection-molding unit comprising a compounder 1,
especially a twin-screw extruder 3, for producing a materially and
thermally homogeneous compound melt 12 of at least one plastic
material and further additives; and a screw-type injection molding
machine 2 with a standard feed zone 6,
characterized in that the exit of the compounder 1 is directly
connected with the standard feed zone 6 of the screw-type injection
molding machine 2 through a connecting unit 8 without
counter-pressure from the screw-type injection molding machine 2,
said injection molding machine 2 has a feed space as a reservoir 10
for a compound continuously produced by the compounder 1; and a
sensor 7 of compounder 1 for measuring the filling level.
[0017] In a particular embodiment, the material from the compounder
1 is directly introduced into the standard hopper of the injection
molding machine 2 without a rigid coupling; and the metering space
acts as a material reservoir 10. Thus, the material 12 relaxes into
a pressureless state, but is naturally recompacted towards the
screw tip, i.e., the congestion space or prescrew space 11.
[0018] In the following, the operation of the device according to
the invention is described with reference to FIG. 1.
[0019] The compounder 1 starts the production of a compound. The
materials to form the compound are introduced through compounder
opening 4.
[0020] The compound is discharged through the start-up valve 9
until some material and thermal homogeneity has been reached.
[0021] When the start-up valve 9 is closed, the materially and
thermally homogeneous compound 12 (compound melt) is conveyed into
the screw-type injection molding machine 2. The screw 5 of the
injection molding machine 2 start to rotate. The rotational
movement of the screw 5 conveys the compound 12 forward, in front
of the screw tip, into the congestion space or prescrew space 11
until sufficient compound for the injection process has
accumulated. Because of the pressure building up in the congestion
space or prescrew space 11, the compound 12 in the screw 5 is
axially compressed.
[0022] By axially displacing the screw 5 towards the nozzle while
the non-return valve 9 is closed, the compound is injected into the
mold cavity with high pressure through the nozzle and the feed
channel.
[0023] During this time, the screw flights of screw 5 that are
provided downstream of connecting unit 8 towards the standard feed
zone 6 of compounder 1 and injection molding machine 2 are filled
with new compound from the compounder 1. At that time, the screw 5
does not rotate.
[0024] In the following cycle, the screw 5 begins to rotate again;
the metering process starts again. This solution according to the
invention in which the connecting. unit 8 is not within the
standard feed zone 6 of the screw 5, but in the zone of the first
third to one quarter of the length of screw 5 in the conveying
direction from standard feed zone 6, achieves by continuous
compound feeding at any rate that all the compound is
injected/metered out in the next injection molding cycle, and old
compound cannot accumulate.
[0025] At the standard feed zone 6 of the injection molding machine
2, a sensor 7 is preferably provided on the one hand, which
monitors the filling level of the injection molding machine 2 and
turns off the compounder 1 when the provided reservoir 10 is
exceeded. On the other hand, or simultaneously, this zone is
applied with vacuum in a specific embodiment.
[0026] For air-sensitive materials, this zone may be purged with
protective gas.
[0027] In a specific embodiment, the compound is directly extruded
into the standard feed zone 6 of the injection molding machine 2.
The compounder 1 is started with the production of compound. The
compound is discharged through the start-up valve 9 until material
and thermal homogeneity has been obtained. Upon the closing of the
start-up valve 9, compound is conveyed into the standard feed zone
6 of the injection molding machine 2, and the screw 5 begins to
rotate. All the compound is conveyed forward thereby, in front of
the screw tip, into the congestion space or prescrew space 11,
until sufficient melt for the injection process has accumulated.
Because of the pressure building up in the congestion space or
prescrew space 11, the screw 5 is axially compressed.
[0028] By axially displacing the screw 5 towards the nozzle while
the non-return valve is closed, the compound is injected into the
mold cavity with high pressure through the nozzle and the feed
channel. During this time, the standard feed zone 6 is used as a
reservoir for the compound. At that time, the screw 5 does not
rotate.
[0029] In the following cycle, the screw 5 begins to rotate again,
and all the compound is conveyed forward thereby, in front of the
screw tip, into the congestion space or prescrew space 11, until
sufficient compound for the injection process has again
accumulated.
[0030] By axially displacing the screw 5 towards the nozzle while
the non-return valve is closed, the compound is injected into the
mold cavity with high pressure through the nozzle and the feed
channel.
[0031] This solution always conveys all the compound in every shot
forward, thus realizing the first in/first out principle.
[0032] A sensor 7 in the standard feed zone 6 monitors the filling
level, and the compounder 1 is controlled accordingly. In a
specific embodiment, this zone is applied with vacuum. For
air-sensitive materials, this zone may be purged with protective
gas.
EXAMPLE
[0033] A commercially available injection molding machine from the
company Engel, Schwertberg, Austria, of the type Engel Duo
23000-17290 and a twin-screw extruder (compounder) from the company
Coperion, Stuttgart, Germany, of the type STS-65 with a processing
section length of 40 D were employed. The twin-screw extruder had a
screw configuration that was common for incorporating fillers, and
possessed gravimetric dosing.
[0034] Through this gravimetric dosing, the formulation, which
consisted of 65% by weight mineral filler (baryte), 17% by weight
thermoplastic olefins (TPO) (Engage), 17% by weight polypropylene
(PP) and 1% by weight usual thermal stabilizers, was metered into
the twin-screw extruder with a discharge rate of 300 kg/h.
[0035] The two machines are connected through a short melt
line/connecting unit, in which a start-up valve is integrated.
Through this start-up valve, the start-up material is discharged
into a quenching tank, which is positioned below the start-up
valve.
[0036] Now, when the signal "formulation o.k." was reported by the
gravimetric dosing, the start-up valve closed after a defined
period of time in order to ensure that no undefined,
non-homogeneous compound is guided into the injection molding
process.
[0037] Upon the closing of the start-up valve, the dosing screw of
the injection molding machine began to rotate and metered the
compound forward and then pressed it into an injection mold.
[0038] During the injection and forward pressing sequence, the
compound produced by the twin-screw extruder was buffered in the
free volume between the connecting unit and the standard feed zone
of the metering screw of the injection molding machine, and then
conveyed completely into the congestion space or prescrew space of
the injection molding machine in the next cycle.
[0039] In this application case, the injection mold was a bulkhead
mold for preparing acoustic components for the automobile
industry.
[0040] However, after corresponding adaptations of the screw
geometry and formulation, the above Example can be applied to any
product on the plant in principle for which the compounding of a
material is economically efficient.
LIST OF REFERENCE SYMBOLS
[0041] 1 compounder [0042] 2 injection molding machine [0043] 3
compounder twin screw [0044] 4 compounder metering opening [0045] 5
injection molding machine screw [0046] 6 injection molding machine
standard feed zone [0047] 7 sensor/measuring of filling level
[0048] 8 connecting unit [0049] 9 start-up valve [0050] 10
reservoir [0051] 11 congestion space or prescrew space [0052] 12
injection molding material
* * * * *